Tetra-t-dodecylamarcapto-p-benzoquinone

ABSTRACT

A lubricating oil composition of improved corrosion, wear and oxidation inhibiting properties consisting of a hydrocarbon lubricating oil composition comprising a major amount of hydrocarbon lubricating oil and between about 0.1 and 10 wt. percent of tetra-t-dodecylmercapto-p-benzoquinone and optionally including additional automative lubricating oil additives such as VI improvers, detergent-dispersants, anti-foamants and supplementary corrosion, wear and oxidation inhibitors.

United States Patent 91 Schlicht [11] 3,764,535 1 1 Oct. 9, 1973 lTETRA-T-DODEC YLAMARCAPTO-P- BENZOQUINONE [75] Inventor: Raymond C.Schlicht, Fishkill, N.Y.

[73] Assignee: Texaco Inc., New York, N.Y.

[22] Filed: May 25, 1972 [21] Appl. No.: 256,855

[52] US. Cl. 252/482, 260/396 R [51] Int. Cl Cl0m 1/42 [58] Field ofSearch 252/482, 393;

[56] References Cited UNITED STATES PATENTS 3,328,301 6/1967 Thompson eta1. 252/48.2 X

FOREIGN PATENTS OR APPLICATIONS 566,055 12/1944 Great Britain 76,83512/1954 Netherlands Primary Examiner-Daniel E. Wyman AssistantExaminerW. Cannon Att0rney-Thomas H. Whaley et al.

[57] ABSTRACT A lubricating oil composition of improved corrosion, wearand oxidation inhibiting properties consisting of a hydrocarbonlubricating oil composition comprising a major amount of hydrocarbonlubricating oil and between about 0.1 and 10 wt. percent oftetra-tdodecylmercapto-p-benzoquinone and optionally includingadditional automative lubricating oil additives such as VI improvers,detergent-dispersants, antifoamants and supplementary corrosion, wearand oxidation inhibitors.

2 Claims, No Drawings TETRA-T-DODECYLAMARCAPTO-P- BENZOQUINONEBACKGROUND OF INVENTION Lubricating oils employed in the lubrication ofinternal combustion engines normally contain additives imparting desiredproperties thereto such as detergentdispersancy, oxidation resistance,corrosion resistance, wear resistance, antifoaming, etc. Since thedemands on the automative lubricating oil compositions have beenbecoming increasingly severe, a greater number and a greater quantity ofadditives in the lube oil for.- mulations have been required. Many ofthe additives employed are metal containing, and therefore, theincreased requirements result in undesirably increased metal deposits inthe engines which in turn result in decreased engine efficiency. Thereis, therefore, a continuing need in the lube oil additive art to developsuperior ashless, i.e., non-metal containing additives, in order toeliminate or reduce engine deposits caused by additive residues.Further, there is a continuing need in the interest of economy and inthe interest of decreasing the chance of inter additive incompatibilityto develop additives which have a multiplicity of functions.

One class of ashless lube oil additives are thetetraalkylmercapto-p-benzoquinones which are broadly known as dopes andextreme pressure agents in lubricating oils (Dutch Pat. No. 76,835).However, the tetra-alkylmercapto-p-benzoquinones specifically describedin the art such as tetra-n-dodecylmercapto-pbenzoquinone are in manyrespects undesirable additives for lube oils in that they increased wearand substantially contributed to the undesirable thickening of thelubricating oil during use.

SUMMARY OF INVENTION Suprisingly, l have discovered and this constitutesmy invention that when one of the previously unrecognized members of thetetra-alkylmercapto-p-benzoquinone class, namely,tetra-t-dodecylmercapto-pbenzoquinone is incorporated in a hydrocarbonlubricating oil it unexpectedly imparts thereto improved wear and oilthickening resistant properties and further imparts thereto unexpectedlysuperior corrosion and oxidation resistant properties.

DETAILED DESCRIPTION OF THE INVENTION More specifically, I have foundwhen tetra-tdodecylmercapto-p-benzoquinone is incorporated in ahydrocarbon lubricating oil in amounts between about 0.1 and wt.percent, it not only does not have the negative properties ofaccelerating oil thickening and contributing to wear attributed tomembers of its class, but actually inhibits oil thickening, promoteswear resistance and in addition is many times superior in promotingresistance to corrosion and oxidation than closely related members ofits class.

The tetra-t-dodecylmercapto-p-benzoquinone additive can be characterizedby the formula:

where R, R and R are alkyl groups such that R R R equal 11 carbon atoms.Specific examples are where R and R are methyl and R is a trimethylhexylgroup and where R and R are ethyl and R is heptyl. Hereinbefore andhereinafter the term t-dodecyl denotes a single isomeric form as well asisomeric mixtures.

The tetra-t-dodecylmercapto-p-benzoquinone additive is incorporated inthe lubricating oil base by standard means such as by direct addition tothe base accompanied with agitation, e.g., stirring, to insure uniformdistribution throughout or may be incorporated as a lube oilconcentrate, e.g., 50-50 50 weight mixture of the benzoquinone and alight lubricating oil (100 SUS at 100 F.) with the concentrate beingadded to the lubricating oil base accompanied by agitation.

Suitable base oils useful in the compositions of the invention as wellas diluent to form the tetra-tdodecylmercapto-p-benzoquinone lube oilconcentrate include a wide variety of hydrocarbon lubricating oil suchas naphthenic base, paraffinic base mineral oils or other hydrocarbonlubricants, e.g., lubricating oils derived from coal products andsynthetic hydrocarbons, e. g., polyalkylene such as polypropylene andpolybutylene of a molecular weight between about 250 and 2,500.Advantageously, the base oils have an SUS'viscosity at 100 F. betweenabout 50 and 2,000 and constitute between about and 99.9 wt. percent ofthe lube oil composition.

In the finished lubricating oil compositions other additives may beincluded. These other additives in addition to supplementary wear,oxidation and corrosion additives, may be any of the standard suitableadditives such as detergent-dispersants, e.g., calcium carbonateoverbased calcium petroleum sulfonates having a total base number ofabout 200 to 500 or more as set forth in U. S. Pat. No. 3,537,996utilized in an amount of between about 1 and 6 wt. percent and/orethoxylated inorganic phosphorus acid free, steam hydrolyzed polybutene(1,000-5,000 m.w.)-P S reaction product as set forth in U. S. Pat. No.3,087,956 utilized in an amount between about 2 and 6 wt. percent, VIimprovers such as the polymethacrylates, e.g., the copolymers of dodecyland octadecyl methacrylates having an intrinsic viscosity in benzene at77 F. of between about 0.1 and l and utilized in an amount of betweenabout 0.05 and 1 wt. percent and antifoamants such as the polysiliconesin amounts of 10 to 1,000 ppm. Exactly what other additives are includedin the finished oil compositions and the particular amounts employeddepends on the particular use and severity to which the finished oilproduct is to be subjected.

The following examples further illustrate the compositions of theinvention but are not to be construed as limitations thereof:

EXAMPLE I This example illustrates a method of preparing thetetra-t-dodecylmercapto-p-benzoquinone additive.

To a reactor there was charged 101 grams (0.5 mole) oft-dodecylmercaptan wherein the mercaptan is composed principally of anisomer of the chemical structure characterized by the formula:

where R and R are methyl and R is trimethylhexyl, 1 13 grams ofnaphthenic lubricating oil of an SUS viscosity of about 100 at 100 F.and 200 mls. of methanol. The resultant mixture was stirred and therewas added to the stirred mixture 21 grams (0.5 mole) of sodium hydroxideat a temperature of 37 C. The resultant reaction mixture was cooled toroom temperature and there was added 32 grams (0.125 mole) of chloranil(tetrachloroquinone) over l-2 hours, the temperature rising to 60 C.Then the resultant mixture was refluxed for 1 hour at 72 C. followed byatmospheric distillation to 100 C. and thence cooled to roomtemperature. The mixture was diluted with pentane, filtered andstripped. The resultant solid product was analyzed and the followingfound: wt. percent sulfur 6.7 (calc. 7 percent), wt. percent sulfur asmercaptan 0.16, wt. percent metal 0.l6 percent calc.), wt. percentchlorine 0.11 (0 percent calc.).

EXAMPLE II p-benzoquinone. Comparative Composition C was identical toCompositions A and B but contained no benzoquinone ingredient. In bothCompositions A and B the formulation was as follows: 89.67 wt. percentparaffinic lube oil of an SUS viscosity of about 130 at 100 F., 0.93 wt.percent of the benzoquinone, 6 wt. percent of lube oil concentratecontaining 44 wt. percent of ethoxylated, inorganic phosphorus acidfree, steam hydrolyzed polybutene (1,200 m.w.)-P S reaction product, 2.9wt. percent lube oil concentrate containing about 50 wt. percent of anoverbased calcium petroleum sulfonate having a total base number ofabout 300 and 0.5 wt. percent of a lube oil concentrate containing 40wt. percent of a copolymer of dodecyl and octadecyl methacrylate inapproximately a 4 to 1 weight ratio, said copolymer having an intrinsicviscosity of about 0.58 in benzene at 77 F. The finished oilformulations ofA and B had a sulfur content of 0.13 wt. percentcontributed by the tetraalkylmercapto-pbenzoquinone, a 0.06 wt. percentphosphorus content contributed by the polybutene-P 5 reaction productand 0.35 percent calcium contributed by the overbased calcium sulfonate.Composition C consisted of 90.6 wt. percent of the lube oil, 6 wt.percent of the ethoxylated concentrate, 2.9 wt. percent of the sulfonateconcentrate and 0.5 wt. percent of the polyacrylate concentrate.

Compositions A, B and C were subjected to three lubrication tests:

The MacCoull Corrosion Test outlined in U. S. Pat. No. 3,549,534 whichmeasures the corrosion in terms of bearing weight loss, the greater theweight loss the greater the degree of corrosion. The MacCoull testfurther measures the degree of oxidative thickening under the MacCoulltest conditions, the greater the kinematic viscosity the greater thethickening.

The second test employed was the Four Ball Wear Test described in U. S.Pat. No. 3,384,588 which is the measure of the amount of wear thelubricating oil permits under engine test conditions. The greater amountof wear, the poorer the ability of the test oil composition to preventsuch wear. This wear is measured in terms of millimeter wear.

The final test was the Oxygen Absorption Test. It measures the number ofhours that it takes for a 25 gram test sample at 340 F. to absorb 500mls. of oxy gen. The longer the time that is required for oxygenabsorption, the greater the resistance of the test composition tooxidation.

Composition A and comparative Compositions B and C were tested and thetest data and results are reported below in Table I:

TABLE I Composition A B C Tetra-alkylmercapto-p- Tertiary Normal Nonebenzoquinone additive Dodecyl Dodecyl MacCoull Corr. Test, 20 hrs.Bearing wt. loss, mg. at 10 hours 5 262 at 20 hours 15 322 Used OilTests (20 hrs.)

Too

Neut. No. 9.2 thick l0.4*) Kin. Visc. at cs. 131.4 to de- 179.8)

termine Oxygen Absorption Test, 340 F. Hrs. to absorb 500 mls. 7.8 4.32.0 0 per 25 g. sample 4-Ball Wear Test, mm. (2 hr./40 kg., 200 F., 600rpm) 0.33 0.51 0.38

*at 10 hours I claim:

1. A lubricating oil composition comprising a major amount of ahydrocarbon lubricating oil containing between about 0.1 and 10 wt.percent of tetra-tdodecylmercaptan-p-benzoquinone 2. A lubricantcomposition comprising between about 2 and 6 wt. percent of anethoxylated, inorganic phosphorus acid free, steam hydrolyzed polybutene(l,000-5,000 m.w.)-P S reaction product, between about 1 and 6 wt.percent of a calcium carbonate overbased calcium petroleum sulfonate ofa total base number between about 200 and 500, between about 0.05 and 1wt. percent of a dodecyl methacrylate-octadecyl methacrylate copolymerhaving an intrinsic viscosity in benzene at 77 F. of between about 0.1and 1.0, between about 0.1 and 10 wt. percenttetra-tdodecylmercapto-p-benzoquinone and the remainder beinghydrocarbon lubricating oil of an SUS viscosity between about 50 and2,000 at 100 F.

2. A lubricant composition comprising between about 2 and 6 wt. percentof an ethoxylated, inorganic phosphorus acid free, steam hydrolyzedpolybutene (1,000-5,000 m.w.)-P2S5 reaction product, between about 1 and6 wt. percent of a calcium carbonate overbased calcium petroleumsulfonate of a total base number between about 200 and 500, betweenabout 0.05 and 1 wt. percent of a dodecyl methacrylate-octadecylmethacrylate copolymer having an intrinsic viscosity in benzene at 77*F. of between about 0.1 and 1.0, between about 0.1 and 10 wt. percenttetra-t-dodecylmercapto-p-benzoquinone and the remainder beinghydrocarbon lubricating oil of an SUS viscosity between about 50 and2,000 at 100* F.